In hex32_arg() and num_arg() error out in case no characters are available
(maxlen = 0).

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
---
Changes v3 -> v4
  - new patch (factored out of patch 'net: pktgen: fix access outside of user
    given buffer in pktgen_if_write()')
---
 net/core/pktgen.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index 3c42ecf17ba2..cb3b732fd0a3 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -761,6 +761,9 @@ static int hex32_arg(const char __user *user_buffer, unsigned long maxlen,
 	int i = 0;
 	*num = 0;
 
+	if (!maxlen)
+		return -EINVAL;
+
 	for (; i < maxlen; i++) {
 		int value;
 		char c;
@@ -808,6 +811,9 @@ static long num_arg(const char __user *user_buffer, unsigned long maxlen,
 	int i;
 	*num = 0;
 
+	if (!maxlen)
+		return -EINVAL;
+
 	for (i = 0; i < maxlen; i++) {
 		char c;
 		if (get_user(c, &user_buffer[i]))
-- 
2.48.1

On Wed, Feb 05, 2025 at 02:11:50PM +0100, Peter Seiderer wrote:
> In hex32_arg() and num_arg() error out in case no characters are available
> (maxlen = 0).
> 
> Signed-off-by: Peter Seiderer <ps.report@gmx.net>

Hi Peter,

This patch and the following could benefit from:

* A more succinct subject
* An explanation of why the change is being made in the patch description

...